Hand crimping tool



Sept. 26, 1961 H. w. DEMLER HAND CRIMPING TOOL 3 Sheets-Sheet 1 Original Filed Nov. 25, 1956 /INVENTOR.

BY He nr U. Dem\e\r Sept. 26, 1961 H. w. DEMLER 3,001,426

HAND CRIMPI NG TOOL Original Filed Nov. 23, 1956 5 Sheets-Sheet 2 IN V EN TOR.

Kenn.) \,J. Demler Sept. 26, 1961 H. w. DEMLER 3,001,426

HAND CRIMPING TOOL Original Filed Nov. 23, 1956 5 Sheets-Sheet 3 y Kenn h). Dem \er 3,001,426 HAND CRIMPING TOOL Henry W. Demler, Lebanon, Pa., assiguor to AMP A Incorporated, Harrisburg, Pa.

Original application Nov. 23, 1956, Ser. No. 624,151, now Patent No. 2,947,207, dated Aug. 2, 1960. Divided .and this application Jan. 7, 1960, Ser. No. 1,034

i 3 Claims. (Cl. ,81-)

This invention relates to hand-operated crimping tools for crimping electrical connectors onto electrical conductors. Hand tools embodying the present invention can be used to apply a variety of diiferent types of crimp to a variety of different types of connectors. However, the utility of the present tool can be most conveniently pointed out with reference to a typical application of the tool and will be so described in the present specification.

Such a typical application is illustrated in FIGURE 9 of the accompanying drawings, wherein the numeral 10 designates a connector comprising a tongue portion 12 adapted to be secured to a binding post or the like and a barrel portion 14. The numeral 16 generally designates an insulated conductor with the insulation stripped from an end portion thereof. The bare end and adjacent insulated portion of conductor 16 are inserted in the barrel 14, after which the barrel is crimped to secure the connector 10 to the end of conductor 16. As shown in FIGURE 9, the barrel 14 of the connector is crimped at two points and 22. The crimp 20 provides a connection between the connector and the bare end 18 of atent conductor 16, and the crimp 22 seals the barrel 14 to the insulation of conductor 16.

The crimping of such a connector to a conductor can be effected by either a power-operated or a hand-operated tool, and tools of both types have been previously proposed. For fixed installations, power-operated tools are generally preferred since they do not have the power limitations of hand-operated tools. On the other hand, there are many cases where ready portability and/or economy are of paramount importance, and in these situations a manually-operatedtool is preferred. The general requirements of such a hand-operated tool are: (1) that it be light in weight and small in size; (2) that it be sufiiciently strong structurally to withstand the usual crimping pressures; (3) that it be capable of delivering the desired relatively high crimping pressures by a simple mechanical movement, e.g., the closure of a pair of handles; and (4) that it have a mechanical advantage such that the necessary high crimping pressure can be delivered by application of relatively little manual force, e.g., the force that can 'be' conveniently applied by a woman operator. I

It is evident that the simplest way of increasing the mechanical advantage of a crimping tool is to increase the length ofthe handles and in a number of previously proposed tools this has been done. However, an increase in the length of the handles also increasesthe weight of the tool which is undesirable.

It is accordingly a' principal object of the present invention to provide a hand-tool which, in relation to its weight, has, a substantially higher mechanical advantage than the tools that have previously been proposed. It is another object of the invention to provide a hand tool that-is capableof developing desired high crimping pressures, andthat is of sufficiently small size and light weight so that it can be. held in and operatedby one hand.

It is evident that the force required to effect a crimp varies as a function of the extent to which the crimping operation has proceeded. For example, in the initial stages of the crimping operation, only a relatively. light force need be applied to deform the barrel 14. On the 3,0MAZ6 Patented Sept. 26, 196i other hand, in the final stages of the crimping operation a relatively large force is required to insure a good electrical contact between the barrel portion of the connector and the conductor. The ideal crimping tool from this standpoint would be one wherein the application of a continuous uniform manually applied input force would produce at the crimping die a force that varies in precise correspondence with the force requirements of the crimping operation. If, for example, the nature of the linkage used in the tool is such that it develops a maximum force at the die when it is only partially closed,.then a larger and heavier tool must be used to efiect a given crimp. In like manner, if the nature of the tool link-. age is such that when it is, for example, half-closed it develops at the die a force that is low in relation to the force required for the crimping operation, then a larger and heavier tool must be used to effect a given crimp. It is accordingly a further object of the present invention to provide a tool having an actuating linkage of such a character that the application of a constant input force produces at the crimping die a force-displacement relationship which closely approaches the force-displacement requirements for crimping a connector. Other objects of the invention will be in part obvious and. in part pointed out hereafter.

The many objects and advantages of the present invention can best be understood by reference to the accompanying drawings which illustrate hand tools incorporating two different embodiments of the invention and wherein:

FIGURE 1 is a side elevation of a hand tool showing the general arrangement of the handles and crimping head, as well as the ratchet mechanism interconnecting the handles;

FIGURE 2is a top plan view of the tool of FIGURE 1 particularly showing the locating head of the connector locating mechanism and portions of the crimping mold adjustingmechanism; FIGURE 3 is a sectional view of the tool taken through plane 3-3 on FIGURE 1;

FIGURES 4, 5 and 6 are vertical sections taken on the lines 44, 5--5 and 6-6 of FIGURE 7 respectively;

FIGURE 7 is a sectional view taken on lines 7-7 of FIGURE 1;

. FIGURE 8 is an exploded perspective view of the central part of the crimping head;

FIGURE 9, as previously indicated, illustrates a connector crimped onto a conductor; and

FIGURE 10 is an exploded perspective view of a portion of the crimping head.

Before proceeding to a detailed description of the structure shown in the drawings, it seems desirable to point out that, in achieving the objectives of the present invention as outlined above, two features of the present hand tool are particularly important. One of these is a manually operable quick take-up link which moves the crimping die into engagement with the connector before the handles are closed to perform the crimping operation proper, so that nearly the full movement of the handles is available for performing the crimping operation itself. A second important feature of this hand tool is the use of a special linkage mechanism which, although somewhat similar to a toggle mechanism, is modified in such mannerthat the manually applied force required to close the handles to crimp the connector is more nearly uni form than it would be with a toggle linkage. The result is that the maximum manually applied force required to crimp a given connector is substantially less using the present linkage than itwould be using a comparable toggle linkage. Also, the linkage mechanism of the present tool permits a much more compact structure to be used than ciuld be achieved with a conventional toggle mechanism.

Referring to the drawings, and more particularly to 7 FIGURE 1, the tool there shown comprises a crimping head generally designated 24, a handle 26 effectively integral with head 24, and a handle 28 pivotally secured to the head 24. The handles 26 and 28 are interconnected by a ratchet mechanism 30 which operates in such man ner that, once crimping of a connector has started, the handles 26 and 28 cannot again be opened until the crimping operation has been completed. Such ratchet mechanisms are known in the art and hence need not be described in detail herein.

Referring now particularly to FIGURES 4 and 8 of the drawings, longitudinally slidable in the crimping head 24 there is a reciprocable plunger 32 made up of the two plates 34 and 36 which are secured together, and are provided at their forward ends with the wire crimping die 38 and insulation crimping die 40 respectively. The die 38 is positioned to cooperate with a mold 42 formed in the crimping head to crimp a portion of the connector onto the uninsulated end of the conductor. The die 40 is positioned to cooperate with a crimping mold 44 formed in the crimping head 24 to crimp a portion of the connector onto the insulation of the conductor. The connector, with the end of the conductor inserted therein, is

connector at two points as previously described. Re-

ciprocating movement of plunger 32 is effected by relative manual movement of handles 26 and 28 in a manner described in detail below.

Referring now to FIGURE 1 of the drawings, the handle 26 at its left-hand end merges into a U-shaped housing 4'6 that effectively forms part of the crimping head. Referring to FIGURE 7, nested within the housing 46 there is a sub-assembly 47 that is particularly shown in exploded perspective view in FIGURE 8. The sub-assembly 47, as shown in FIGURE 8, com-prises in general a locator mechanism supporting block 48, the plunger 32 and the plunger guide plate 50.

Pivotally connected to the rear end of plunger 32 there is a quick take-up link 52 that has a bifurcated upper end 54 which embraces the rear end of the plunger and is pivotally secured thereto by a pin 53. The handle 28, which is of generally U-shaped cross-section, terminates at its left and in a pair of ears 28a and 2817 that embrace both the link 52 and the central portion of plunger 32. The cars 2811 and 28b are pivotally connected to the link 52 by a pin 56.

- It has been previously pointed out that handle 28 at its left-end is pivoted to the crimping head. This pivotal connection is established by means of a pin 58 (see FIG- URE 8) which is mounted in the block 48- and passes through ear 28b of handle 28, the plunger 32, car 28a of handle 28 and plate 50. The plunger 32 (see FIG- URE 5) has a slot 59 formed therein to permit reciprocating movement of the plunger with respect to pin 58.

Referring to FIGURES 4 and- 5 of the drawings, the crimping molds 42 and -44 are formed in a crimping mold supporting block 60that extends into the housing 46. More specifically, and as best shown in FIGURE 7, the inner end of the crimping mold block fits between the lower portions. of the locator mechanism support block 48 and the side plate 50 and is secured to these parts, as well as to the housing 46, by a pair of rivets 62 and 64 (shown in FIGURE 8).

Referring now to FIGURE 10, the wire-crimping mold 42 is formed in the main portion of block 60, whereas the insulation-crimping mold 44 is formed on one end of a slidable member 6.6 constructed and arranged to slide in a recess or track 68 formed in the block 60. Both the member- 66 and track 68 have upper and lower walls that diverge inwardly in such manner as to prevent movement of member 66 other than the desired sliding movement;

along the track. The member 66 is positioned along track 68 to provide a desired clearance between the insulation-crimping die and insulation crimping mold in a manner that will now be described.

Referring to FIGURES 5 and 10, positioned within the block 60 there is a mold position adjusting pin 70 having a knurled knob 72 at its lower end. At its upper end the pin 70 is provided with a laterally extending arm 74 adapted to engage one of a series of slots 76 formed in the top of block '60 in such manner that the pin is latched against rotation. A spring 78 interposed between the knob 72 and block 60 is biased to urge the pin 70 downwardly and thereby urge the arm 74 into one of the slots 76.

Near its upper end, pin 70 is provided with two fiat surfaces 80 and 82 located at different distances from the center of the pin. The pin is partially located within a recess 84 formed in the member 66. The construction is such that the pin 70 acts as a stop to limit outward movement of member 66 and thus of mold 44. When the pin is in assembled position, the periphery of the pin is adapted to engage the inner edge of recess 84 and limit outward movement of member 66 when a connector is crimped. In this position of pin 70, there is minimum clearance between die 40 and mold 44. If it is desired to increase the clearance between the insulation die and mold, the pin is moved manually upward by means of knob 72 to release arm 74 from one of the slots 76 and then rotated counterclockwise and released to cause the arm 74 to fall into another slot 76. When the pin has been thus rotated, flat 80 is in a position to engage the inner edge of recess 84 and thus provide a greater clearance between die 40 and mold 44 during crimping. By rotating pin 70 another 90, flat 82 can be positioned to engage the inner edge of recess 84 and thus still further increase the crimping clearance between the insulation die and mold.

Referring now particularly to FIGURE 6 of the drawings, the connector locator mechanism is mounted in the block 48 as previously described. The locator mechanism comprises a head 86 having a neck 88 that extends into a bore formed in the block 48 and is secured therein to a shaft 92 which extends through the remaining portion of bore 90 to and beyond the right-hand end of the block 48. Near its right-hand end the bore 90 opens into a larger bore 94 that is internally threaded to receive a nut 96. The nut 96 has a central hole therein of suflicient diameter to permit flee movement therethrough of the shaft 92. The bore 90 and shaft 92 define an annular space Within which there is a spring 98 that bears at its left end against the neck 88 of locating head '86 and at its right end against the nut 96, the spring being under compression to urge the locating head 86 to the left as viewed in FIGURE 6.

The portion of shaft 92 to the right of block 48- extends through a hole in an operating lever 100 that is pivotally secured to block 48 near its lower end by a pin 102. The right-hand'end of shaft 92 is threaded to receive a pair of lock-nuts 104 that are threaded onto the shaft in such manner as to secure it loosely to lever 100. Clockwise rotation of lever 100 about pin '102 causes the shaft 92 and with it the locating head 86 to be drawn to the right as viewed in FIGURE6. Theupper end of shaft 100 extends through an opening 106 formed in the housing 46 and is provided at its upper end with the serrations 108 to facilitate pivoting of lever 100 to retract the locating head 86. I

Reverting now to FIGURE 1 of the drawings, it has been previously pointed out that the. lever 52 is pivotally secured to the plunger 32 by a pin 53' and to the handle 28 by a pin 56, and that handle 28 is effectively and pivotally secured to the crimping head by a pin 58. The lever 52 is urged in a clockwise direction around its pivot 56 by a spring 120, shown in dotted lines in FIGURE 1. The spring '120 is loosely mounted on pin 56 and has two extending arms-122 and 124 thatbear respectively against the interior of handle 26 and the lever 52,. the spring being biased to urgelever 52 clockwise and thereby retract plunger 32. Lever 52 extends through and' beyond handle 28 when the parts are in the position shown in FIGURE 1 to form a finger piece 126, by means of which link 52 can be manually rotated to advance the plunger. v

The operation of the above-described tool is as follows: A conductor is inserted in a connector, and the connector and conductor are inserted in the tool. When the connector has been properly positioned for crimping, link 52 is rotated counter-clockwise by manual pressure on the finger piece 126 to advance the plunger until the crimping dies are in contact with the connector. The rotation of link 52 is essentially independent of the closing movement of the handles. However, referring to FIGURES l and 4, it will be apparent from a consideration of the locations of pivots 53, 56 and 58 that, as link 52 is rotated counter-clockwise, pivot 56 will be drawn a short distance toward the axis of the plunger and a slight closing movement of the handles will occur. The tool illustrated is so constructed that this slight closing movement of the handles causes the ratchet 30 to become engaged. Thus, when the link 52 has been manually rotated to a position in which finger-piece 126 is flush with handle 28, it cannot be rotated clockwise by spring 120 until after the handles have been fully closed and the ratchet 30 has become disengaged. This action ensures proper crimping of the connector as the handles are forced together.

It should be noted that, in the tool of FIGURE 1, the quick take-up link is effectively perpendicular to the path of motion of the plunger when the handles are open. More particularly, with the handles open, the line connecting pivots 53 and 56 forms approximately a right angle with the line connecting pivots 53 and 58.

This arrangement of the quick take-up link provides several advantages. In the first place, it permits a relatively wide angle between the handles in the open position to be used, since the tendency of the tool to lock or bind when such a wide angle is used is overcome by manual rotation of the quick take-up link. Also, because of the perpendicular relationship referred to above, the tool is positively locked in open position until the link is manually rotated, and hence inadvertent closure of the handles is avoided. Moreover, rotation of the quick take-up link advances the plunger into contact with the connector to be crimped with only a slight closing movement of the handles, and therefore almost the entire closing movement of the handles is available for the crimping operation proper.

The particular type of linkage used in the present tool also contributes to the attainment of the objectives set forth at the beginning of the specification. It should be noted that the pivot 56 moves away from both crimping dies during closing movement of the handles and that pivots 53 and 58 approach one another as the handles are closed. This action is quite different from that of a conventional toggle and as previously pointed out above provides a tool wherein the peak manual force required to crimp a given type of connector is substantially less than it would be if a conventional toggle linkage were used. Moreover, the present linkage provides a more compact structure than a toggle mechanism would provide. As a practical matter, this means that the present linkage can be used to build an exceptionally small tool which will develop the necessary high crimping pressures with the application of only a moderate manual force.

A further feature of the present structure is that the pivots 53 and 58 are aligned with the central axis of reciprocation of plunger 32. This central location of the pivots provides a balanced and more effective conversion of manual pressure on the handles into crimping force at the crimping dies and increases the mechanical advantage of the tool.

From the foregoing description, it should be apparent that hand tools incorporating the present invention are capable of achieving the several objects set forth at the beginning of the present specification. By using the combination of quick take-up link and special linkage described above, a small light-weight hand tool canbe constructedwhich develops a surprisingly high maximum crimping force. The quick take-up links. 52, etc. permit the use of a relatively wide handle opening since they provide a means whereby the pivot 53 can be shifted toward the crimping dies in the head of the tool before an effort is made to close the handles. Also they permit the lost motion of the plungers to be taken up before significant starting movement of the handles occurs, and hence a relatively large angular movement of the handles is available for a given displacement of the plunger. It has been found that, by using the structure of the present invention, hand tools can be made no more than 6" long which develop surprisingly high and quite satisfactory crimping pressures.

It is, of course, to be understood that the foregoing description is illustrative only, and that numerous changes can be made in the preferred embodiment described above without departing from the spirit of the invention. For example, the quick take-up link can be used in conjunction with a linkage other than the specific modified toggle linkage described and shown in the drawings. In like manner, by shifting the pivots 53 and 56, an operative tool can be made without using the quick take-up link. The pivot 58 can be spaced somewhat from the axis of plunger 32, although preferred results have been obtained by locating pivot 58 at or close to the plunger axis, i.e., in substantial alignment with pivot 5.2 in the direction of movement of the plunger. Other modifications within the scope of the invention will be apparent to those skilled in the art.

This application is a continuation-in-part of my copending application, Serial No. 391,269, filed November :10, 1953, and now Patent No. 2,800,042, and a division of application, Serial No. 624,151, filed November 23, 1956, and now Patent No. 2,947,207.

I claim:

1. In a hand tool for crimping electrical connectors in combination, a crimping head having a first crimping die therein, a plunger mounted for reciprocating motion in said head and having a second crimping die positioned to cooperate with said first die to crimp a connector placed in the path of said glunger, a pair of handles connected to said head and plunger to reciprocate said plunger, one of said handles being fixed to said head and the other handle having a first pivot near one end thereof, and a link connected to said other handle by a second pivot spaced from said first pivot, said link having a third pivot near one end thereof, said first pivot being connected to said head and the third pivot being connected to said plunger, whereby relative movement of said handles reciprocates said plunger, said link, when said handles are open, being substantially perpendicular to the path of movement of said plunger and having a manually operable extension by which it can be rotated about said second pivot, whereby said handles are locked in open position and can be closed only after said link has been manually rotated to move said plunger toward its crimping position, said first pivot connected to the head and said third pivot connected to said plunger, and the axis of the plunger disposed parallel to the axis of the head whereby closing movement of the handles causes the plunger to move in a direction away from the handles.

2. In a hand tool for crimping electrical connectors in combination, a crimping head, a plunger mounted for reciprocating motion on said head, means on said head and plunger for crimping a connector, handle means for reciprocating said plunger, including a plurality of handles,

one of said handles being fixed to said head and the other the link comprises an extension of the link which fnneiions handle pivoted to said head, and a link connected to said as a lever.

other handle by a second pivot, said link having a third f' pivot connected to said plunger, whereby relative move- References c m the f $jP i ment of said handles reciprocates said plunger, said link, 5 UNITED STATES PATENTS when said handles are open, being substantially per-pen- 498 N D 5O dicular to the .path of movement of said plunger, and 5 m 'f'j'i'f'i means for rotating said link about said third pivot. FOREIGN PATENTS 3. The device of claim 2 wherein the means for rotating 7 95 3,249 France May 16, 1949 

